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The presence of an increasing number of organic pollutants in the water poses serious issues to human health and the environment. Many of these organic pollutants are persistent and nonbiodegradable. The pollutants of fresh water by harmful pollutants require researchers to develop innovative, efficient, sustainable, and cost-effective materials for water treatment. Advanced oxidation processes have the potential to efficiently degrade organic pollutants from water. The photocatalytic process uses catalyst and light to produce radicals. Radicals possess a high redox potential, e.g., hydroxyl radicals E° = 2.72 V that react with the molecular structure of various pollutants and degrade pollutants into harmless products. Thus, photocatalysis is recognized as a favorable approach to tackling pollutant removal and saving energy. However, semiconductor photocatalysts have limitations such as photo-generated charge carrier recombination, wide band gap energy, and slow surface reaction kinetics. Disadvantages can be remedied by appropriate modifications of physico-chemical, and optical properties of TiO2. Overcoming the limitations present in TiO2-based photocatalysis, as well as the search for potentially efficient materials, is extremely important, and the modification of TiO2 with carbon-based materials like graphene is promising due to its unique properties. Therefore, graphene and its derivatives have been widely used as supports for semiconductor materials and photocatalysts due to their distinctive physio-chemical, optical, and electrical features. In this research, an attempt has been made to utilize the excellent properties of graphene by coupling it with TiO2 nanoparticles. Synthesis of nanocomposites of TiO2 with reduced graphene oxide has been done by hydrothermal/solvothermal synthesis followed by calcination at 300 °C. Prepared nanomaterials were characterised using scanning electron microscopy, Xray diffraction, Raman spectroscopy, and transmission electron microscopy. Photocatalytic degradation was performed using methylene blue as a model pollutant under simulated solar light (300W Osram Ultra Vitalux bulb) as a source of irradiation. The obtained results of performed photocatalytic tests show the improved removal rate of methylene blue dye from an aqueous solution using prepared TiO2@rGO nanocomposite in comparison with bare TiO2 nanoparticles. [ABSTRACT FROM AUTHOR]

Nowadays, investigations based on nanotechnology undertake breakthroughs in many application areas such as manufacturing, materials, nanoelectronics, energy, biotechnology, medicine, information technology and others. Excellent properties of graphene-based materials, that are crucial in wide range of applications, continuously highlight this promising new compound. Among them is for example graphene oxide (GO). It is an oxidized form of graphene with oxygen functional groups (carboxyl, hydroxyl, carbonyl, and epoxy) in the carbon lattice. However, the oxidation of graphite to GO introduces defects into the carbon structure that result in significantly altered physio-chemical properties, which are in some application undesirable. One way to overcome the difficulties is to consider reduced graphene oxide (rGO) with decreased oxygen content. Material has altered physicochemical properties such as optical and surface functionalities, originating predominantly from higher electron mobility. The present work addresses the synthesis of GO, and rGO by introducing a simple approach and provides structural, morphological, chemical and physical analysis of the synthesized material. GO was prepared by chemical oxidation and exfoliation of graphite flakes (particle size = 50 µm) using Hummer's method. rGO was, on the other hand, prepared by the hydrothermal method. Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and Raman spectroscopy were used to evaluate characteristic of this already known material. Results show that GO and rGO synthesized by the presented method, exhibit properties suitable for wide range of applications such as in supercapacitors, water purification, and also as composite materials in coatings and even solar cells. [ABSTRACT FROM AUTHOR]